Temperature gauge, sender or something else

[dirtmover]

Went to take the kids out today and noticed that when I started the boat the temperature gauge was pegged at max. Now I wasn't observant enough to notice if it started like this or rose during the first 5 minutes of running. As soon as I noticed I panicked and turned the ignition off. Of course after a few moments of thought I realised that >250F was an impossibility.

I restarted it an immediately the gauge pegged at max again. Brought it out of the water, put some muffs on and restarted it. The water outlet was hot but not overso. Still pegging at max. Left it 30 minutes or so to cool. This time when I started it the water was cold. Thermostat obviously OK. Checked out the wiring from sender to gauge and pulled connections to check for corrosion. Started it again and still pegging at max. This time, with the engine still running, I disconnected the sender. The gauge dropped back to zero but when I reconnected the gauge went up to where I expected (about 130F). Sopped it, restarted it multiple times and everything is OK.

Any ideas what might be wrong here?

 

[Bifflefan]

Re: Temperature gauge, sender or something else

Had a bad connection.

Dont over think the problem.

 

[Don S]

Re: Temperature gauge, sender or something else

Did you by any chance open up the engine hatch and touch the engine to see if it was really hot ?????????? IF not, why not?

Could be a bad sender, bad gauge, bad wiring, bad impeller, and you could have a real overheat. But you have to check the engine to know where to start.

 

[dirtmover]

Re: Temperature gauge, sender or something else

Thanks for the input guys.

I did reseat the connecors at both ends and it still read max. It was only after I pulled and reconnected the sender connector with the engine running that it started to behave normally.

There was no real overheat. First thing I checked was the engine temp with my hand. Also when out the water with muffs the water exiting the engine was hot but not scalding - as the gauge suggested. Also the temp switch for buzzer did not back up the gauge info.